Vibration damper



April 18, 1939. i R 5 K 2,154,489

VIBRATION DAMPER Filed Sept. 28, 1937 2 Sheets-Sheet 1 April 18, 1939.

R. S. BUCK VIBRATION DAMPER Filed Sept. 28, 1937 2 Sheets-Sheet 2 IN VEN TOR. [WC/73rd 5 Buck ATTORNEY Patented Apr. 18, 1939 PATENT OFFICE YIBBATION DAMPER V S. Buck, Wethersileid, Coma, assignor :to United Aircraft Corporation, East Hartford.

- Coma. a corporation of Delaware A plication September as. 1931, Serial No. 166.078

- 11 Claims.

This invention relates to improvements in vibration reducing means and has particular reference to a vibration reducing means for a power plant such as an internal combustion engine.

An object of the invention resides in the provision of improved means for cushioning vibrations produced by an engine in the process of develop-- i P A further object residesiin the provision of a m resilient hydraulic driving connection between a power plant and a device driven thereby.

A still further object resides in the provisionofa resilient connection interposed between a driving and driven element effective to change the hatural frequency of harmonic vibration of the drivingelement and driven element combination.

Other objects and advantages will be more particularly pointed out hereinafter or will become apparent asthe description proceeds.

In the accompanying drawings in which like reference numerals are used to designate similar parts throughout, there is illustrated a suitable mechanical embodiment of what is new considered to be the preferred. form of the invention.

The drawings. however. are for the purpose of illustration only and are not to be taken as limiting the invention. the scope of which is to be measured by the scope of the appended claims.

In the drawings,

tion of an engine and power transmitting reduction gear.

Fig. 2 is a front elevational view of the internal combustion engine having a vibration damper incorporating this invention, portions being broken away and shown in sections to better illustrate the construction thereof.

Fig. 3 is a sectional view on an enlarged scale of the vibration damping elements particularly 4 illustrated in Fig. 2 showing the application thereto of a valve arranged to automatically vary the restriction to the flow of hydraulic fluid to the vibration damping portion of the apparatus. and

Fig. 4 is a view similar to Fig. 3 showing the application to the vibration damping apparatus of a temperature controlled valve for variably restricting the flow of hydraulic fluid to the vibration damping portion of the apparatus.

Referring to the drawings in detail the engine 54) illustrated by way of example for the purpose of this disclosure is a geared internal combustion engine particularly adapted to drive an aeronautical propeller for the propulsion of an aircraft. The engine itself may be of anysuitable form. and

the invention maybe applied with equal facility to Fig. 1 is a sectional view of a fragmentary par-- spigot healing H in the end of the hollow crankshaft to and is additionally supported by antlfriction bearing lficarrie'd by the engine nose piece It through which the power shaft extends. in

The power shaft i2 is rotatable relative to the crankshaft l0 and is operatively connected thereto by a planetary reduction'gearing. A drive gear 20 is non-rotatabiy secured upon the end of the crankshaft i0 and is supported for rotation by the .bearing 22 mounted in the transverse partition member 24. -The drive gear 20 meshes with a plurality of planetary gears, afsis indicated at 26, rotatablymounted upon respective axles 28 carried by a cage 30 splincd to the power shaft l2. At their inner sides the planetary gears 26 mesh with a-relatively fixed sun gear 32 which is carried upon a bearing pad u interposed between it and the sleeve portion of the cage member 30. Oil for lubricating the engine or for operating a 2:. controllable pitch propeller driven by the engine may be carried to the interior of the hollow power shaft l2 through the oil collector ring 36 and radial apertures 38: A flanged ring member 40 surrounds the ring 38 and also constitutes a re- :1" taining member for supporting one side of the bear it against lateral movements with respect to the opening in the nose piece 18 in which the bearing is mounted. A cover member 42 supports the opposite side of the hear I 6 and encircles a nut .44 screw-threaded upon the power she ft to clamp the inner race of bearing Hi between itself and a shoulder 48 on the shaft to restrain the shaft against axial movements with respect to the nose piece of the engine.

The reduction gear construction so far described is well-known to the art and it is believed that a more detailed description thereof is unnecessary for the purpose of this disclosure.

Usually the sun gear element 32 is rigidly secured to the engine nose piece to restrain it against rotation and render it effective as a reaction member for the force imparted to the planetary gears 26 by the drivegear 20 so that the cage 30 will be caused to rotate about the sun gear carrying with it the drive shaft H at a speed less than the rotational speed of the crankshaft It. In accordance with the present invention. however. the sun gear 32 has rigidly secured to the flange sleeve portion 46 thereof an apertured ievr' 48 which extends radially outward ticularlylillustraied'ln Fig; '2. and includes" a pair of cylinders, one'bf'which is indiila'te'd at 50, rigid ly secured to respective pads as indicated at 52 formed on the engine nose piece I8, and pistons,

one of which is indicated at El, slidably mounted in respective cylinders 60 and connected by means of suitable connecting it to the respectiveope positely disposed lever portions'of the member. 43.,

As the two opposed parts of the hydraulic mechanism are exactly similar; it is considered that a detailed description 0! only one of the similar parts is suflicient for the purpose of this disclosure.

The cylinder is supported in tangential alignment with the respective lever portion of the member Id, and the piston rod 56 is pivotalLv connected to the lever portion, as indicated at 58, and is likewise pivotally connected to the piston by a suitable wrist pin, as indicated at 60. Where the rod 58 extends outside or the nose piece It, it is enclosed in a suitable oil tight jointed casing, as indicated at 81. At its end opposite the pad 5!, through which .the piston rod 56 extends, the cylindenis providedswlth a head 64. which carries a plurality of valves, as indicated at 66 anddl The valve 68 is connected through the manuallyactuatable valve 66 withv a line 10 leading from -asource of fluid under pressure. The valve 58; hasan actuating portion I2 which extends within-the cylinder 50 in position to be contacted by th'eouter end of the piston 54 as the piston moves outwardly in the cylinder. .If the piston moves the actuating element I2 outwardly to a predetermined position, the valve I58 isopened to admit additional fluid to the-space between the head 64 and the piston .84 to force the piston backwardly in the cylinder.-

From the construction so far described, it will be observed that rotation of the sun gear 32 is resisted by the compression ofthe fluid trapped in the space between the piston 54 and the head 61 of the cylinder ill and that the amount of pressure exerted; upon this fluid may be measured to indicate the torque being ,exerted by the engine. In order to measure this fluid pressure a iiuidrline 14 may be connected at one end with the channel l6 which leads through thehead 64 and opens into the space l8 between the piston and the cylinder head. At its opposite end the fluid line" isconnected with .a suitable pressure gauge, not illustrated, which may if desired, be directly calibrated in torque units.

One or more auxiliary cylinders, as indicated at Ill, may bemounted upon the head 64 of the cylinder 50. The auxiliary cylinder, or each of.

the'several auxiliarycylinders, contains a slidable piston 82 having its closed or head end opposed to the adjacent surface oithe head 64. An oil passage ll leads from the passage 16 to thespace I! between the piston 82 and the adiacent surface 01 the head 64 so that when presinto the space I6 andtend to force the piston 12 outwardly in the cylinder The oil passage "is preferably; restricted orifice. There may 2,154,4so I l be one such passage it for each piston 82 or i larly shown .in Flg. 4- or'valves controlled by the pressure of the surrounding fluid. as particularly shown in Fig. 3. .The restricted passage 84 acts to damp the flow of oil and thereby convert at least a portion of the energy of vibration into heat in the hydraulic fluid. Movement of the piston 82 is opppsed by some suitable resilient means, tor instance by a compression spring 88, which is received at one end in the cup-shaped piston 82, and at the other end in the cup-shaped end of -an abutment 9i! screw-threaded into the open end oi. the cylinder 80 and retained in ad- 'justed position therein by the lock nut 92. A

vent channel leads from the space between the piston 82 and the abutment to some suitable sump such as the interior of the nose piece i8 so that movement of the piston 82 will not be interfered with by compression or any fluid in the space between-the pistonand the abutment and this channel also ccnnects,"through a restricted passage, with the compression space in the cylinder 50*to maintain acontlnuous flow of oil throughthe cylinder and thereby avoid the eflects oi trapping appreciable quantities oi air in the -cylinder..-. =A screw'valve controls the drainage of fluid through the channel 84.

With the above described constructionit'will be observed that anyroughness or unevenness in the :rotation of the crankshaft Ill caused by the operation of the'engine may be transmitted alternatively either to the cage 30 or to the sun gear 32. It the sun gear is rigidly fixed, the vibrational forces will betransmitted to the cage: however, if the sungear has a limited freedom of resiliently resisted rotational movement, this movement may be used. to absorb the amplitude of the uneven vibrational forces delivered by the crankshaft. With the sungear restrained against rotation by the hydraulic mechanism, illustrated in Fig. 1; and exerting its reactive force against the hydraulic fluid and the spring balance piston 82, the sun gear may be given sufficient freedom of resiliently resisted rotational movement -to cause a flow of oil through orifice 84 and movement of spring 88 and thus absorb vibrational forces. delivered by the crankshaft. With the above described mechanism, the rotation of the power shaft I! may for all practical purposes be rendered uniform and'vibratlonless, at least, insofar as rotational vibrational forces of the engine are concerned. By suitably proportioning the size and number of the passages B4 and/or the characteristics of the spring 88, the device may be rendered most eflicient in absorbing any selected band or hands of vibrational forces.

In the form oithe invention illustrated in Fig.3, an apertured washer or partition member 98 is disposed between the channel It and the interior of the small cylinder 8|). This partition member maybe conveniently held in place by inserting it in an internally screw threaded aperture provided in the head of the main cylinder 50 and screwing the small cylinder-[lo down upon -it.- The small piston 82 is 'provldedwith an extension I00 which projects through the aperture in-the partition member 98 and is provided with "taperingslots as indicated at lei :so that the small cylinder;

a partition member I04 isclamped between the "small cylinder 80 and the head of the large cylinder 50 and, as illustrated, is retained in an internal recessprovided in the open end of the This partition member is provided with a substantially coaxial aperture therethrough as indicated at I06 and with a substantially diametrical well or bore which rotatabiy receives a valve stem I08 having a flat portion adjacent the aperture I06. This valve stem egrtends through the portions oi the cylinders 50 and adjacent to the partition member I04 and into a sealed compartment H0 provided on the exterior of the head 6, of the cylinder 50 and connected with the channel 16 and with the conduits ll. Within the compartment I I0 a thermostat III in the form of a coiled bimetallic strip is connected to the end of the valve stem I08 and to the casing of the compartment H0 in such a manner that in coiling or uncoiling in 'response to changes in the temperature of the fluid flowing through the compartment it turns the valve stem I08 to vary the restriction of the orifice I08. While there has been illustrated and described a suitable mechanical embodiment of what is now considered tobe the preferred form of the invention, it is to be understood that the invention is not limited to the particular constructional form 50 illustrated and described but that such changes in the size, shape and arrangement of parts may be resorted to as come within the scope of the appended claims. V Having now described the invention so that others skilled in the art may clearly understand the same, what it is desired to secure by Letters Patent is as follows:

1. In combination with a driving element subiect to torsional vibrations, a driven element, and a power transmitting reduction gear having a reaction element interposed between said driving and driven elements, a torque indicating and torque variation reducing device operatively associated with said reaction gear element comprising, a main variable volume fluid displacing device operatively connected with said reaction gear element to resist torque reaction induced by rotation thereof, and an auxiliary variable volume device of relatively small inertia and small capacity resiliently urged toward its minimum capacity connected to said main variable volume device to receive fluid displaced therefrom and provide for said reaction element a limited freedom of vibration absorbing movements opposed by fluid friction damped resilient force.

2. In combination with a driving element subject to torsional vibrations, a driven element. and a power transmitting reduction gear having a reaction element interposed between said driving and driven elements, a main variable volume device operatively connected with said reaction gear element to oppose rotational movements thereof by converting the rotational force imposed on said reaction elements into fluid pressure. and means for reducing vibrational forces between said driving and driven elements comprising, an auxiliary variable volume device of relatively slight. inertia connected to said main variable volume device by a restricted orifice, and means resiliently opposing changes in volume of said auxiliary variable volume device to permit in said main variable volume device relatively small vibration induced volumetric changes opposed by fluid irlctlon damped resilient force.

3. In combination with a driving element sublect to torsional vibrations, a driven element, and a power transmitting reduction gear having a reaction element interposed between said driving and driven elements. a main piston operatlvely connected to said gear reaction element, a relatively flxed cylinder for said piston. and means comprising, a second cylinder, an auxiliary piston of relatively slight inertia ,reciprocable in said second cylinder, and means resilientlyopposing movements of said auxiliary pistonto permit relatively slight vibration induced movements of said main piston to absorb vibrational forces between said driving and driven elements.

4. In combination with a driving element subject to torsional vibrations, a driven element, and a power transmitting reduction gear having a reaction element interposed between said driving and driven elements, a piston operatively connected to said gear reaction element. a relatively iixed cylinder for said piston, means for maintaining fluid under pressure in thev space between said piston and the head of saidcylinder, and means for maintaining the pressure of said fluid substantially constant. a

r 5. In combinationwith a driving element subject to torsional vibrations. a driven element, and a power transmitting reduction'gear having a reaction element interposed between said driving and driven elements, a piston operatively connected to said gear reaction element, a relatively fixed cylinder for said piston, means for maintaining fluid under pressure in the space between said piston and the head of said cylinder, a second cylinder connected with said flrst mentioned cylinder and a spring balanced piston in said second cylinder to absorb pressure surges in the hydraulic fluid in said first mentioned cylinder.

6. In combination with a rotatable driving element subject to relatively high frequency torque variations, a driven element, and a power transmitting reduction gear having a torque reaction element, a piston operatively connected to said gear reaction element, a relatively fixed cylinder for said piston, means for maintaining fluid under pressure in the space between said piston and the head of said cylinder, and resilient means hydraulically connected with said space to absorb gigs; frequency pressure surges in said hydraulic '7. Vibration reducing means for a torque transmitting drive comprising, a hydraulic piston and cylinder device operatively connected to said drive in such a manner that torque transmitted by said drive tends to move said piston, and hydraulic pressure actuated means resiliently resisting movement of said piston, and a restricted hydraulic passage between said piston and cyllnder device and said hydraulic pressure actuated means.

8. Vibration reducing means for a torque transmission drive including a torque reaction element comprising, a relatively large hydraulic expanslble chamber device operatively connected with said torque reaction element, one or more torque variations intochanacs in=1luid pressure,-

resilient means 102' relieving increases in fluidpressure caused by torquevariations of frequency likely to producefiibratioriadd means ior variably restricting the flow of fluid said pressure relieving means.

10. Vibration reducing means for a torque transmitting drive comprising, a hydraulic piston 10 and cylinder device operatively connected to said drive in such a manner that torque transmitted :bysaid drive tends to move said piston. and means comprising, an auxiliary cylinder of small capacity connected with said torque opposing cylindcrp anauxiliary piston of inertia ca Patent no. 2,151 M9.

to and 1mm csmmm or" ooiumc'rlou.

- -"-,1s4,4eo

mission comprising; means-for transniittinr of relatively small amplitude and relatively high frequency. andlmeans for indicating the average pressure of said fluid. 1

' f RICHARD S. BUCK.

April 1 19 9.

Yar ow s.. Boos.

Itis hereby-certifiedfthat error appears in the printed specification fer tiie abov e' numbered patent correcti dnas followfs: Page i first column, line 1, second' colmm, l nes, claims --9 mo 11 respectively, for the transmitting read transmutirig j thatjtiie said Letters Patient should be read with this correction therein that ths same may conform to the recorder the casein the Patentpfljice. l'signed and sealod this- 15th a or mm, A: n. 19 9.

i iSeal) Leslie Frazer Acting Gommissioner of Patents.

torque variations intochanacs in=1luid pressure,-

resilient means 102' relieving increases in fluidpressure caused by torquevariations of frequency likely to producefiibratioriadd means ior variably restricting the flow of fluid said pressure relieving means.

10. Vibration reducing means for a torque transmitting drive comprising, a hydraulic piston 10 and cylinder device operatively connected to said drive in such a manner that torque transmitted :bysaid drive tends to move said piston. and means comprising, an auxiliary cylinder of small capacity connected with said torque opposing cylindcrp anauxiliary piston of inertia ca Patent no. 2,151 M9.

to and 1mm csmmm or" ooiumc'rlou.

- -"-,1s4,4eo

mission comprising; means-for transniittinr of relatively small amplitude and relatively high frequency. andlmeans for indicating the average pressure of said fluid. 1

' f RICHARD S. BUCK.

April 1 19 9.

Yar ow s.. Boos.

Itis hereby-certifiedfthat error appears in the printed specification fer tiie abov e' numbered patent correcti dnas followfs: Page i first column, line 1, second' colmm, l nes, claims --9 mo 11 respectively, for the transmitting read transmutirig j thatjtiie said Letters Patient should be read with this correction therein that ths same may conform to the recorder the casein the Patentpfljice. l'signed and sealod this- 15th a or mm, A: n. 19 9.

i iSeal) Leslie Frazer Acting Gommissioner of Patents. 

